Mai Ngọc Tiến - HK08 - Thuyền bay giữa kỳ

7/31/2019 Mai Ngc Tin - HK08 - Thuyn bay gia k

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Thit k thuyn bay (WIG) 2012

1

Mc lc

Mc Trang

Chng 1. Gii thiu thit k. 2

1.1 Gii thiu chung v thuyn bayWIG. 2

1.2 Phn loi thuyn bay 4

1.3 Nhu cu thc t v thuyn bay nc ta 5

Chng 2. Thit k tng . 7

2.1 Cc khi nim c bn v hiu ng mt thong. 7

2.2 Mc ch v nhu cu thit k. 11

Chng 3. Thit ks b. 12

3.1 Tnh ton s b. 12

3.2 Xc nh dng hnh hc ca cnh v thn. 17

3.3 Tnh ton cc lc tc dng ln thuyn bay

3.4 Thit ks b Cabin. 21

3.5 Kt lun thit ks b. 23

Chng 4. Tnh ton kt cu. 244.1 Kt cu thn thuyn bay. 25

4.2 Phn tch ti tc dng ln cnh. 26

4.3 Tnh ton gii hn mi. 33

4.4 Vt liu. 33

Chng 5. Phn tch n nh v thit kiu khin. 34

5.1 Khi nim n nh. 34

5.2 Kho st n nh kh ng. 38

5.3 Kho st n nh thy ng. 41

Chng 6. Kt lun. 43

Ti liu tham kho.


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Chng 1. Gii thiu thit k .

1.1 Gii thiu chung v thuyn bayWIG

Khi qut.Trong nhiu th k qua, nhu cu di chuyn trn bin ca con ngi ngy cng tng cng vis pht trin ca cc phng tin di chuyn trn bin. Cc loi tu th h mi th ngy cngnhanh hn, cc cng ngh mi c gii thiu u l tng tc ca chng. V thc t l c rt nhiu phng tin t c tc rt cao vo khong 100km/h nh tu cnh ngmhay tu m kh. Nhng cc phng tin ny li c hn ch l mun t tc cao th lii hi cng sut ln v tiu hao nhiu nhin liu.

Hnh 1.1 Tu cnh ngm. Hnh 1.2 Tu m kh.

Yu cu cng sut ln ca cc loi tu tc cao c nguyn nhn ch yu l do lc cn nht ln, mhn 50% l do ma st vi mt nc. Cc gii php c a ra l gim thiu s tip xc ca tu vimt nc. iu ny dn ti vic pht trin mt loi phng tin p ng c cc yu cu v tccng nh gim thiu ma st vi mt nc l thuyn bay (WIG).

Thuyn bay (WIG Wing in ground effect) hot ng cao gn b mt nc trn mt mkhng kh p sut cao c to ra gia cnh v mt nc. m kh ny c to ra bi stng tckh ng gia cnh vi mt nc, c gi hiu ng mt t.


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Ti sao li chn thuyn bay ?V kinh t

Tiu tht hn 50% nhin liu so vi cc loi my bay thng thng nhng li c tc lnhn 15% so vi cc loi tu thuyn tng ng.

Yu cu csh tng cho vic hot ng v bo dng thuyn bay khng cao. Chi ph bo tr thp. Thi gian khu hao ngn.

V an ton

C khnng tn nh, d dng x l. Trong trng hp ng c b hng, c th h cnh t t xung mt bin Ngoi ra khi bin ng, n nh ca thuyn bay cao hn cc loi phng tin ng thy

khc.

Khng say sng hay say my bay.V mt sinh thi

Mc tiu hao nhin liu thp dn n vic gy nhim khng kh thp. Khng gy nhim nc. Dng nc v khng kh xung quanh lm mt ng c. Hu nh khng c sng. Khng gy hi n thm thc vt khi s dng trn cc con sng,

khng c thit hi cho mi trng nc.

Ting n thp.Mt hn ch ca thuyn bay

Cng ngh ch to cha pht trin mnh, nguyn nhn ch yu cn tr s pht trin cathuyn bay l vn vn nh dc. Vn chnh l khi tch ra khi mt nc, do sc cnca nc ngay trc khi thuyn bay ct cnh l rt ln nn cng sut yu cu nhc cthuyn bay ln l kh ln so vi cng sut bnh thng vn hnh. Do cng sut tng cao khict cnh nn thuyn bay c nguy c mt n nh dc, lm cho thuyn bay d xy ra hintng hoc nghing ln trn hoc hng xung di v gy tai nn.

Ph thuc nhiu vo iu kin thi tit nh cao sng v tc gi. Thuyn bay nh th km hiu quhn so vi mt chic ln v thm ch cn nhy cm hn

vi iu kin thi tit xu.

Kt lun,i vi nhng ng dng nht nh th cc li ch m thuyn bay mang li vt xa nhnghn ch v vy thuyn bay l mt s la chn kh thi so vi cc phng tin vn ti khc. Mt nhhot ng s xem xt nghim tc vic s dng thuyn bay nu mt siu kin v yu cu c png.Mt syu tc cc nh u t xem xt l:


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S chnh lch v tc Mt chic thuyn bay c thit k tt s c t sL/D tng i cao v tc thp so vi mt mybay ng ngn c kch thc tng t, nhng n li nhanh hn rt nhiu v hiu qu nhin liu tthn so vi thuyn cao tc.

Hiu qu

Hiu qu nhin liu, lng nhin liu s dng cho mi hnh khch trn mi km, th t l vi nghcho ca hiu qu vn ti, n l mt thc o v hiu qu c bit ph hp so snh cc loiphng tin vn ti khc nhau hot ng tc khc nhau. Ni chung, mt phng tin hiu quhn th c hiu qu vn ti cao hn, c lp vi vn tc v L/D ca n.

Hnh 1.3 T s cng sut v trng lng ca cc phng tin khc nhau.


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Gi thnh hot ngKhnng tit kim nhin liu cao ca thuyn bay cht c nhng chic c kch thc ln.Nhng chic nh phi bay cao thng i cao trnh sng, do hiu qu nhin liu ca mtchic thuyn bay nhcng tng tnh mt chic my bay chuyn dng. May mn thay cc chi phhot ng ca thuyn bay khng ch bao gm chi ph nhin liu, m n cn gm chi ph bo tr,

thuyn vin, bo him,y mi l li th thc s ca thuyn bay so vi cc my bay ng ngn.Do bn cht hng hi ca thuyn bay, chi ph xy dng v bo tr s rhn nhiu so vi my baythng thng. Ngoi ra, vic o to phi hnh on cng i hi t hn, do s gim c chi ph.

C sh tngMt li th r rng ca thuyn bay l tnh linh hot ca n, khng cn ng bng. Tt nhin thuynbay sc gii hn hot ng ti khu vc ven bin, h ln, ni chiu cao sng c gii hn.

An tonMc d c th xem s an ton ca mt chic thuyn bay l tuyt vi v n lun gn mt nc,nhng n khng phi khng c vn tim n. Thuyn bay cn c mt chiu cao bay ti thiu chiu qu nhin liu, do n lun bay cao thp nht c th, ph thuc vo chiu cao sng thct. Vn l sng c chiu cao khng bng nhau trn cqung ng bay. Cc php o trong thct cho thy chiu cao sng thng c chiu cao trung bnh, nhng i khi li xut hin mt ln sngrt cao, c th cao gp 34 ln so vi chiu cao sng trung bnh.

Mt kha cnh an ton khc l nhng trngi nh giao thng, hi o, cu. Vic ny i hi phi ch thng radar dn ng cn bo tt.

1.2 Phn loi thuyn bay (WIG)

Mt thi gian trc y ngi ta cha xc nh r thuyn bay l my bay hay l thuyn. Do mt sc thbay c, mt s li khng. Thuyn bay c khi c lm bi cc hng tu, c khi li do cchng my bay. l l do v sao s phn loi ca thuyn bay v cc yu cu hot ng ca n vnchac r rng. Mt s th chu thm quyn ca IMO (International Maritime Organization - Tchc hng hi quc t), mt s li thuc thm quyn ca ICAO (International Civil AviationOrganization - T chc hng khng dn dng quc t) v mt s li thuc c hai. Do thuyn bay chyu hot ng ct cnh, h cnh v bay l l trn mt nc nn n thuc thm quyn qun l ca Tchc hng hi quc t IMO, nhng mt s chic thuyn bay khc n c ch to bay mkhng cn c hiu ng mt t, tc l c th bay ln cao, lc ny thuyn bay li thuc thm quynqun l ca T chc hng khng dn dng quc t ICAO.


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Sau y l bng phn loi s b ca thuyn bay [Tham kho 1]

Loi Thm quyn M t

HSB IMO Khi hot ng lun tip xc vi nc.

Loi A IMO Khng th hot ng khi khng c hiu ng mt thong.

Loi B IMO/ICAO

C th tm thi tng cao vt qua nh hng hng ca hiu ngmt t nhm trnh vt cn. Nhng n khng th duy tr sut chuynbay m khng c hiu ng mt t, ng nng c chuyn i thnhth nng.

Loi C IMO/ICAOC kh nng bay ti cao khng chu nh hng ca hiu ng mt t.Cao hn cao ti thiu m mt chic my bay cn t c theo tiuchun ICAO

1.3 Nhu cu thc t v thuyn bay nc ta

iu kin t nhin nc ta vi 3200km bbin cng h thng sng ngi chng cht dn n nhucu v cc loi phng tin di chuyn trn a hnh ny l rt ln. Vi nhng u im rt ln vcc c tnh k thut so vi cc loi tu thuyn ang hot ng hin nay th thuyn bay hu hn sem li mt gii php di chuyn thun tin, nhanh chng m li an ton cho nc ta.

Nhu cu ln nht ca thuyn bay l phc vi li, du lch trn bin cng nhu sng h. Vi lngkhch du lch c nhu cu du lch bin o, tham quan sng nc ngy cng cao th yu cu vphng tin i li thun tin, nhanh chng cng tng v l c hi pht trin thuyn bay. Ngoira, thuyn bay cn c thp ng nhu cu vn chuyn hng ha (c bit l cc loi hng ha cnvn chuyn nhanh nh hi sn, rau c, th t, bu phm), nhu cu v cu h, cu nn, khai thc

du kh, qun s

Qua cc iu kin trn, ta thy c thtrng ca thuyn bay l rt ln, nhu cu v thuyn bay lrt phong ph nn vic pht trin thit k v ch to thuyn bay l vn rt thit thc.


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Chng 2. Thit k t ng.

2.1 Cc khi nim c bn v hiu ng mt thong

2.1.1 V mt khng hc [Tham kho 1]

K t khi bt u cc chuyn bay c ngi li, cc phi cng c kinh nghim cm nhn c mthin tng l l ngay trc khi h cnh c cm gic ging nh my bay khng mun xung thphn na. My bay ch mun tip tc bay do lp khng kh b kt gia cnh v ng bng, to thnhmt m khng kh. Lp m kh ny c cm nhn r nht nhng my bay c din tch cnh lnv c vtr t cnh thp. Hin tng ny c gi theo kh ng hc l hiu ng mt thong.

L thuyt hiu ng mt thong tm hiu v hiu ng mt thong, u tin chng ta si vo tm hiu mt sc tnh ca cnhmy bay c lin quan n hiu ng ny. Nh chng ta bit lc nng c to ra trn cnh l do s

chnh lch p sut gia mt trn v mt di cnh, p sut mt di cao hn mt trn cnh to plc y cnh i ln. Vic chnh lch p sut gia hai mt cnh to ra cc xoy xung quanh u micnh (wing tips), cc xoy ny lm tng lc cn trn cnh.


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C nhiu yu tnh hng n ln lc nng kh ng hc m cnh to ra. Lc nng ph thucvo hnh dng, kch thc, nghing, v iu kin dng chy ca khng kh i qua cc i tng.i vi mt cnh ba chiu, n c thm nh hng ln lc nng gi l downwash.

i vi mt lc nng cnh, p sut khng kh mt trn ca cnh thp hn so vi p lc bn dicnh. Gn 2 bn mi cnh, khng kh t do di chuyn t khu vc ca p sut cao vo khu vc p

sut thp. Khi my bay di chuyn di bn tri, mt cp xoy ngc c hnh thnh u micnh. Cc xoy u mi cnh to ra dng downwash ca khng kh pha sau cnh rt mnh gn ucnh v gim i vi gc cnh. V tr gc ti ca cnh c tng bi dng gy ra bi downwash.Cc thnh phn downwash ca lc ny c gi l cn cm ng bi v n l dng xung v c"kch thch" bi cc chuyn ng ca cc xoy ui. Lc nng gn u micnh c nh ngha lvung gc vi dng chy cc b. Cc dng cc b c mt gc tn ln hn so vi dng chy t do vdng cm ng. Cc xoy ny lm lch hng dng kh xung sau cnh sau ca cnh. Thnh phnvn tc lm dng kh b lch xung gi l vn tc downwash. Vn tc downwash lm cho gim gcti ca dng kh nn dn ti gim lc nng. b li gc ti th ta phi tng gc ti, khi tng gc ting ngha vi vic tng lc cn. Ta gi lc cn ny l lc cn cm ng.


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Trong iu kin bnh thng, my bay bay l do chuyn ng ca cnh my bay trong khng kh tora p sut tnh mt di cnh cao hn so vi mt trn cnh sinh ra lc nng trn cnh. Khi bay lncao, mt trn cnh my bay s c vn tc dng cao hn mt di dn ti p sut b gim to ra schnh lch p sut 2 mt ca cnh v lm xut hin dng kh tdi y ln, to thnh hin tngxoy ui lm tng lc cn cm ng.

Hnh 2.1 Cc xoy cc iu kin bay khc nhau.

Trong hu ht cc trng hp, my bay bay trong dng tdo ni m khng c ranh gii gii hn sdch chuyn ca khng kh. Tuy nhin, thuyn bay c lm s dng hiu ng mt t (groundeffect), v ng nh tn gi thuyn bay bay trn mt mt thong ranh gii gn vi mt di cacnh. Khong cch gia mt thong v cnh thay i gn li vi nhau lm tng lc nng v gim lccn. Hin tng ny c th coi l s chng chp ca 2 hiu ng ring bit: hiu ng chord cnh(CGE - chord ground effect) v hiu ng si cnh (SGE - span ground effect).

Trong hiu ng CGE, c chng sau sthay i c tnh kh ng ca cnh l s thayi p sut tnh mt di cnh. iu ny xy ra do p sut tng hp (bao gm p suttnh v p sut ng) ca dng xung quanh cnh khng i. Khi khong cnh gia cnhv mt thong nh, lp khng kh bn di cnh b nht li vn tc dng kh gim dnn vic lm gim p sut ng v do lm p sut tnh tng tng ng. Sgia tngp sut tnh l nguyn nhn lm tng lc nng trn cnh.

Cc xoy khi bay mt cao.

Cc xoy b nn khi gn mt thong

Cc xoy b kha bi mt thong


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Trong khi CGE lm tng lc nng th hiu ng SGE li lm gim lc cn. Nh bit,lc cn tng cng gm 2 thnh phn chnh l lc cn hnh dng v lc cn cm ng. Lccn hnh dng l do ma st b mt cnh vi dng kh, cn lc cn cm ng l do hintng xoy ui to ra lm gim hiu qu ca cnh. Trong hin tng SGE, cc xoy bgii hn bi khong cch gia cnh v mt t, iu ny lm gim nh hng ca xoy.Bi vic sc mnh ca cc xoy gim i nn cnh xut hin mt t s AR (aspect ratio)

cao hn t s AR hnh hc ca n. T l thuyt dng lc nng ca Prandtl, lc cn cmng t l nghch vi h s AR, do hiu ng mt thong dn n vic lm gim lc cncm ng.

Hnh 2.2 Hiu ng mt t nh hng n lc cn v lc nng.

Cng ngh cnh c hiu ng mt t hot ng tt vi ba nguyn l ni ting nhng mt cch ngngc nhin l n li t c nh gi co vnguyn l kh ng hc. [Tham kho 3]

Th nht, hiu qukh ng v khnng nng ca cnh tng ln ng k khi hot ng cao thp hn mt na chiu di si cnh so vi mt nc hoc mt t, c gi l hiu ngmt t. Hiu ng mt t l hin tng gy ra bi s hin din ca mt ranh gii gia mt

t v cnh, n lm thay i dng kh xung quanh cnh v hn ch dng downwash ra khiu cnh. Dng downwash thng lm tng ng k lc cn cm ng khi n ha trn vcun vi dng kh i qua bn di cnh. Trong hiu ng mt t, dng kh chy qua bndi cnh c nn nhiu hn v t ri hn khi cnh trong t do. iu ny cho php hiu qutrn ln nhiu hn vi dng khmt trn ca ui cnh. Khi mt cnh c thit k thchhp hot ng gn mt b mt, lc nng tng ln khong 45% v lc cn gim xung 70%so vi hot ng ca mt cnh tng t trong dng t do.


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Hnh 2.2 Hiu qu ca hiu ng mt thong.

Th hai, hiu ng Coanda, cn c gi l lp ranh gii nh km, l xu hng ca mtdng lu cht gn lin vi mt b mt li, ch khng phi theo mt ng thng theo hngban u. Hiu ng Coanda c ng dng quan trng trong cc thit b tng cng lc nngkhc nhau ca my bay, nh khng kh di chuyn trn cnh c th b un cong v pha mtt bng cch s dng flap v mt ng c phn lc thi trn b mt cong tng lc nng.

Th ba, lc nng trn cnh stng nu dng kh trn cnh c gia tc bi ng c x vntc cao. Chnh bi s kt hp ca lc y ng c, lc nng kh ng truyn thng v lcnng y c tng cng, n c thlm tng hiu qu ca hiu ng mt thong.

H s lc nng theo hnh dng cnh


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Hnh 2.3 Hiu ng Coanda.

Vn n nh dc ca thuynbay cng rt quan trng, n rt d b lt ngc ra sau. Nguyn nhnl do tm p sut ca lc nng c t xa ui v n di chuyn ra pha trc khi bay ln cao khi

tc dng ca mt thong to ra moment ngc ln. Vn ny c th gii quyt bng cch dng uingang ln.

Hin nay, bin dng cnh s dng vi hiu ng mt thong cng c thit k ti u cho thuynbay. c trng c bn ca bin dng cnh thuyn bay l chng thng c y phng v dng y lith lm gim lc nng, cn y lm c xu hng lm tng mt n nh. Bn knh mi cnh cngkhng nn qu nh khng xy ra hin tng tch ri lp bin di tc dng mnh ca hiu ngmt thong.

2.1.2 V mt thy ng hc[Tham kho 1]Hu ht cc thuyn bay u hot ng trn nc hoc t nht l lng c v d c mt s v dxut v mt chic thuyn bay trn cn, nhng chng l rt t. Ni chung, thuyn bay s khng c linquan vi nc khi bay bng, v vy chng chlin quan n nc khi ct v h cnh.

Khnng hot ng trn binKhnng hot ng trn bin ca thuyn bay c biu hin chiu cao sng ln nht c th ctcnh, bay bng v h cnh. Mt s thng s trng thi cho thy rng chiu cao sng ln nht khi ctcnh v hcnh l nh nhau v tng i thp, cn khi bay bng th c thcao hn. Trong gii hn

an ton, thuyn bay phi c chun b hcnh trong trng hp ng c b hng hoc trnghp khn cp, ngay c khi bay qua sng d kin cao nht. Do , khnng hot ng trn bin cathuyn bay c xc nh bng chiu cao sng ct v bay bng / chiu cao sng khi h cnh. Tmquan trng ca nh ngha ny trong thc t l cng sut lp t c xc nh bi chiu cao sngcao nht khi ct cnh, trong khi bn kt cu ca thn c xc nh bi chiu cao sng cao nhtkhi h cnh (hay bay bng), ni m ti thy ng lc l cao nht. Lu rng iu ny chc cch khi vn tc ct cnh v hcnh l nh nhau.

Dng kh n v dichuyn theo b mtcong


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Cng sut thaLch s ch ra rng lc cn ca thuyn bay khi ct cnh th ln hn khi bay bng. iu ny cngha l khi ct cnh ng c phi hot ng vi cng sut ln hn khong 30-40% so vi khi baybng. Mc d y ch l mt minh ha vnh hng ca hiu ng mt thong, nhng n khngc mong chbi v thit hi v trng lng v gi c. Cng sut tha khng thc s dng

tng vn tc bay bng bi v bn thn mi chic thuyn bay c mt gii hn tc , khi vt qu tc an ton th thuyn bay s trnn mt n nh.

Lc cn v vn tc ct cnhS khc bit v cng sut c th gii quyt bng cch gim ti a lc cn khi ct cnh. Lc cn trongqu trnh ct cnh bao gm nhiu thnh phn, trong ng k l cc lc thy ng do nht vlc cn ca sng. Lc cn nht do ma st gia thn tu v nc. Lc cn sng l nng lng mt ido sng p vo thn tu.

Khi mt vt di chuyn trong nc s to thnh mt lp sng bao. Sng ny trnn cao hn khi vntc tng v ngc li. Kt qu l lc cn sng t ti a ti vtr no trc khi ct cnh. Lc cnti a ny gi l lc cn hump v vn tc khi gi l vn tc hump. i vi thuyn bay lccn hump sxc nh cng sut u vo.

Hnh 2.4 Biu lc y v lc cn ca 2 chic thuyn bay.

Tc ti a trn l thuyt l im ti m cc ng lc y ct ng lc cn trn th. ykhng phi l tc ti a trong thc t, do tc ti a trong l thuyt c th vt qu tc anton cho php ca thuyn bay.


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Nhiu thy phi c c thit kcnh v flap tinh vi to nhiu lc nng nhm gim vn tc ct cnhcng nh gim ti v lc cn thy ng. Bng cch ny h s lc nng lc ct cnh c th ln gp 10ln so vi lc bay bng. iu ny li khc i vi thuyn bay, n khng th tn dng y ccflap, vic ny gii hn h s lc nng ca thuyn bay. Cch d dng nht gim thiu vn tc ctcnh l thit k ti trn cnh thp, nhng vic ny li gii hn vn tc ti a khi bay bng.

Thit k thn tuThit kthn tu thng b b qua khi thit k ci thin hiu sut ct cnh, v h chthng tptrung vo thit kkh ng hc. Nhiu tnh nng ca tu cao tc v thy phi c c th hu dng tng h s thy ng L/D. R rng l thit k thn tu thy ng hc l khng hn gin, n ihi chuyn mn v mt nh thit k thuyn bay nn quan tm. Mt vi thuyn bay hin nay c thitkkh ng rt tinh tnhng thit k thy ng li rt km.

2.2 Mc ch v nhu cu thit k

tng thit k thuyn bay (WIG) l chuyn chdu lch trn bin gia t lin vi o vgia cc o vi nhau. So vi cc phng tin cng mc ch khc, chic thuyn bay c nhng uim ni tri c v mt k thut v kinh t, theo c tnh tc ca thuyn bay gp 2-7 ln tu bin,v chi ph hot ng ch bng 1/3 n 1/5 so vi my bay thng thng. V vy, nhu cu v thuynbay l rt thc t.

Thc tnc ta l cha c chic thuyn bay no nn ban u chng ta s thit k khng qu phctp nhng vn c th th nghim vo thc t. Theo , chic thuyn bay ca chng ti thit k schc 6 ngi (gm 1 phi cng v 5 hnh khch), di chuyn trn qung ng khong 100kmvi vn tc chng 80km/h.


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Chng 3. Thit k sb3.1 Tnh ton s b

Bng thng s k thut ca mt s loi thuyn bay c thit k v ch to thnh cng.

WIGTrng lngct cnh (kg)

Payload(kg)

Vn tc baybng (km/h)

Chiu cao baybng (m)

Cng sut(hp)

Sngi

X-114H 1600 150 130 0.175 210 6

Airfish-2 580 120 120 0.1 70 2

Airfish-3 760 220 120 0.1 75 4

Hoverwing 2VT 1160 230 135 1 90 2

Airfish 8 860 220 160 1 330 8

3.1.1 c tnh khi lng

Thuyn bay c thit k ch6 ngi bao gm 1 phi cng v 5 hnh khch.

Khi lng trung bnh ca mt ngi cng hnh l l 75kg (v mc ch ch yu phc v du lch nnkhi lng hnh l khng ln lm).

Tng khi lng ca hnh khch v hnh l (payloadd) l Mp = 75 * 6 = 450 kgDa vo kt qu ca mt s mu thuyn bay:

Tn X-113 (1971) Airfish-3 (1990) Airfish-3 PA(1992)

Hoverwing2VT (1997)

Airfish-8(2001)

Payload91 kg 220 kg 220 kg 230 kg 220 kg

Khi lngct cnh

360 kg 760 kg 860 kg 1160 kg 860 kg

Vi s pht trin ca cng ngh vt liu mi, chng ta hon ton c th p dng vo thit k thuynbay gim khi lng ca n. Nhli th, ta c th k vng thit k thuyn bay vi t s khi

lng payload vi khi lng ct cnh l 1 : 1

Nh vy, ta sc c tn khi lng s b ca thuyn bay l M = Mp * 2 = 900 kg

Trng lng ca thuyn bay W = 900 * 10 = 9000 N


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3.1.2 Xc nh h s lc nng CL v t s h/c

u tin, ta tin hnh la chn bin dng cnh theo hai tiu ch l to c h s lc nng cao ngthi phi m bo cho my bay v mt n nh. Hin nay khng c nhiu bin dng cnh c thitkc bit cho hot ng trong hiu ng mt t. Cc nh thit k thuyn bay thng phi s dngcc bin dng cnh bit trc y ca my bay cho thuyn bay ca h, v d nh bin dng

NACA. Mt bin dng cnh khc cng c s dng ph bin l bin dng Clark Y, bi v mtdi phng ca bin dng ny va tng lc nng li kh n nh, rt thch hp vi hiu ng mt t.Gn y, cc chic thuyn bay hin i lun c bin dng cnh c ti u ha cho tng trng hpc th.

Cc nh kh ng hc c xu hng thit k bin dng cnh theo ng cong camber v vic phn bdy. Nhng vic ny ch thch hp i vi my bay hot ng trong dng t do, cn trong hiung mt t hnh dng mt di cnh l rt quan trng. Trong nhiu trng hp, cc nh thit kthng chn hnh dng mt di cnh phng bi v va to c nhiu lc nng li n nh tt, numt di cnh li c th trong tnh hung c th s dn n ht mt di lm gim lc nng, cn

mt di qu lm th li l gim n nh tnh dc.

Sau y l mt vi kho st v bin dng cnh:

Xt bin dng cnh NACA 0012, gc tn 5o th h s lc nng Cl0.6, cnh khng c camber, mt di cnh li.

Hnh 3.1 c im bin dng cnh NACA 0012.


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Bin dng cnh NACA 4412, gc tn 5o th h s lc nng Cl 1.2, bin dng ny mtdi phng, lc nng kh ln.

Bin dng cnh Clark Y, gc tn 5o th h s lc nng Cl 1.13, bin dng ny cng rtph hp vi hiu ng mt t.

Hnh 3.2 c im bin dng cnh NACA 4412 v Clark Y.

Qua mt s kho st trn, nhm quyt nh chn bin dng cnh NACA 4412 vi gc tn 3o. Davo bng thng s t bo co ca ch Hunh Thy Ha Mi lp Vit Php 99:

Bindng

Gcti

h/c (%)

1 3 5 7 9 11 13 15

NACA

4412

3 1.336 1.186 1.101 1.046 1.007 0.978 0.955 0.936

4 1.415 1.310 1.236 1.183 1.143 1.111 1.086 1.065

5 1.472 1.399 1.339 1.292 1.255 1.225 1.200 1.179


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Ta c bng th

Hnh 3.3 Biu lin h gia Cl v h/c.

Da vo biu trn ta chn h sh/c = 0.1(v y c xem l la chn thch hp) vi h s lcnng l Cl = 1.

3.1.3 Xc nh din tnh cnh v cc thng skch thc cnh

Phng trnh lc nng: Vi cc thng strn thay vo phng trnh ta c:

Vy din tch cnh s b l 30 m2.

Vi iu kin sng nc ta, chiu cao sng trung bnh khong h = 0.5m, vy ta c c chiu dico cnh s b l c = 5m.

Nu chn cnh hnh ch nht th ta c S = b*c => si cnh b = 6m.

Bin dng cnh NACA 4412 nn b dy cnh t = 12%*c = 12%*5 = 0.6m

0

0.2

0.4

0.6

0.8

1

1.2

1.41.6

0 5 10 15 20

Cl

h/c (%)

NACA 4412

3 4 5


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3.1.4 T s L/D v tng lc cn

Ta c t s

Tham kho ti liu ta c th quan h gia L/D max v t s h/b

V ta chn loi cnh NACA 4412 trn nn t t s gia b dy airfoil vi di chord l 12% vh/b = 0.083 tnh trn,ta suy ra L/D max khong 8.

3.1.5 Cng sut ng c

Vi bng thng s cc loi thuyn bay hin nay.

WIG Trng lng ctcnh (kg)

Cng sut (hp) Cng sut ti(kg/hp)

X-114H 1600 210 7.6Airfish-2 580 70 8.2Airfish-3 760 75 10

Hoverwing 2VT 1160 90 12.8

Airfish 8 860 330 2.6

T bng trn ta c c cng sut ti trung bnh l khong 9 kg/hp. Vi khi lng thuyn baynhm chng ti thit k khong 900kg th cng sut ti c lng s vo khong 100 hp.

Vy ti c lng cng sut ng c dng cho thuyn bay vao khong 100 hp.


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3.2Xc nh dng hnh hc ca cnh v thn3.2.1 Dng hnh hc cnhTrong thit k hnh hc ca cnh, chng ta quan tm n 4 thng s quan trng

Bin dng cnh (airfoil) Gc swept ca cnh Taper ratio (t s gia chord tip/chord root) Aspect ratioa) i vi bin dng cnh, c c hiu ng mt t cao nht th bin dng cnh vi mt

di tng i phng hoc hi lm l la chn ti u v n va to c nhiu lc nng mli va n nh. Qua cc phn tch trn, chng ti chn bin dng cnh NACA 4412 chothit k cnh ca thuyn bay.

Hnh 3.4 Bin dng cnh NACA 4412.

b) i vi gc swept ca cnh, nh thit k hay quan tm ti tnh nng ca my bay s vnhnh iu kin di m, ngang m hay trn m. Trong trng hp ny my bay ta angthit k s bay bng 80 km/h, iu kin mt nc bin th vn tc m thanh vo khong

300 m/s. T my bay c th bay sMach 0.07 tng ng vi iu kin di m. V thi vi mu thuyn bay ny th gc swept l iu khng tht cn thit.

Hnh 3.5 Thng s hnh hc cnh.


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c) i vi Taper ratio, t s ny nh hng ln n ng i ca dng kh qua cnh hay v trtch lp bin ca dng kh qua cnh. Vi cc t s taper ratio khc nhau ta c tngv tr tchri lp bin trn cnh khc nhau.

Hnh 3.6 V tr tch ri lp bin ng vi tng Taper ratio.

Do tch ri lp bin s gy ri vng hu lu nn s gy ra mt n nh phn b p sut, t lgim lc nng trn cnh. V vy nu ch xt chn loi cnh no khc phc iu ny, ta s chncnh tam gic c taper ratio bng 0 do ch tch ri lp bin tip l vng c din tch nh nht. Th

nhng ta cng c th chn cnh hnh ch nht do tnh cht d ch to, cnh ln hn ng ngha vilc nng s nhiu hn v ng nhin ta phi ch ti cc bin php khc phc tch ri lp bin khis dng loi cnh ny.

Cnh c nhiu dng hnh hc khc nhau vi nhng u nhc im khc nhau, chng ta cn phntch cc c im ca tng dng hnh hc khc nhau c c dang hnh hc cnh thch hp.

Cnh hnh ellip cho ta lc cn cm ng nh nht nhng rt kh khn trong vn thit k ch to.


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Cnh hnh ch nht vi chord bng hng s dc theo si cnh th ddng ch to nhng li lmtng lc cn cm ng.

Cnh hnh thang hay c h s taper cr/ct th va c lc cn cm ng chp nhn c (gn ti u) mli va d ch to.

Cc dng hnh hc ph bin nht l delta, hnh ch nht Trong cnh delta c s dng phbin nht bi v hnh dng cnh ca n cho php bay n nh vi hiu ng mt t. Vn ln nhtca thuyn bay l thit k cnh vi hiu ng mt t sao cho nng ln khi mt nc tc thp, lm gim lc ko ca nc.

Vi nhng phn tch trn, nhm chng ti quyt nh chn cnh delta ngc (mt dng ca cnhhnh thang) cho thuyn bay.

Hnh 3.7 Cnh delta ngc.

Leading edge

Trailing edge

rr

t

Chordtip


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d) i vi Aspect ratio,Nh cc tnh ton s btrn ta c din tch cnh l 30m2, chord cnh trung bnh cm = 5m, si cnhl b = 6m v h s aspect ratio AR = b2/S = 1.2

Ta c cch xc nh cnh delta

Hnh 3.8 Cnh tnh cnh delta ngc.

Ta c cng thc tnh din tch nh sau: ( ) vi f l b rng thn (ta tnh ton s b th b rng thn l 1m), si cnh b = 6m.

= 10m

c tnh s b cr = 7m v ct = 3m h s taper ratio = 0.43

Sau y l hnh dng tng quan thit k cnh ca thuyn bay:

Tip

chord

Root

chord

AC

25%

Leading edge

Chord

root

Chordtip


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Hnh 3.8 Thit ks b 1 bn cnh.

3.3 Tnh ton cc lc tc dng ln thuyn bay

Cc thnh phn lc cn gm Lc cn kh ng Lc cn hnh dng (ch yu l lc cn ma st) Lc cn sng

L

c cn th

y ng

Lc cn kh ngLc nng kh ng theo vn tc 2

1

2LL V SC


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vn tc (m/s) Lc nng (N)1 18

2 74

3 165

4 294

5 459

6 662

7 900

8 1176

9 1488

10 1838

11 2223

12 2646

13 3105

14 3602

15 4134

16 4704

17 5310

18 5954

19 6633

20 7350

Lc cn ma st kh ng Ta c t s chiu cao trung bnh mt thong ca thuyn bay so vi si cnh l

0.50.083

6

h

b

0

1000

2000

3000

4000

5000

6000

7000

8000

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20

Lc nng (N)


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Ta tra bng thtrn tm c t smax

7L

D

=> Ta c h s lc cn

1

7 7

LD

CC

Bng phn b lc cn kh ng theo vn tc

vn tc (m/s) Lc cn kh ng (N)1 3

2 11

3 24

4 42

5 666 95

7 129

8 168

9 213

10 263

11 318

12 378

13 444

14 515

15 591

16 672

17 759

18 851

19 948

20 1050


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Lc cn cm ng theo vn tc2

201

2

i

e

LD

V S eAR

vn tc (m/s) Lc cn cm ng (N)1 5

2 20

3 44

4 78

5 122

6 176

7 2398 312

9 395

10 488

11 590

12 702

13 824

14 956

15 1097

16 1248

17 1409

18 1580

19 1760

20 1951

0

200

400

600

800

1000

1200

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20

Lc cn kh ng (N)


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Lc cn chuyn ng ca thn thuyn bay khi di chuyn trong ncKhi thuyn bay chuyn ng trong nc s xut hin lc thy ng, m tr s ca n ph thuc vokhi lng ring v nht ca nc. Khi lng ring (kg/m3) ca nc t thay i khi thay ip lc, vy coi nh nc khng nn c v ng cht, nhng khi lng ring ca nc li thayi nhiu theo nhit .

Ta s dng s liu ca Nga vi:

nhit t = 4o C: nc ngt = 1000 kg/m3, nc mn = 1025 kg/m3 nhit t = 15o Cv p sut 760 mmHg, khng kh 1.226A kg/m3, trng lng ring

ca nc . 9810g N/m3.

H s nht dng lc (kg/m.s) l i lng c trng cho tnh cht tng loi cht lng, t thay itheo p sut, nhng li thay i nhiu theo nhit .

H s nht ng hc (m2/s) l gia tc ca lc nht xut hin trong cht lng

Do tc dng tng h gia tu v cht lng, nn dc theo mt t h mt lc xut hin v phn b

lin tc. Ti mi im trn , vct cng ca lc mt l nP .

Sc cn quyt nh n lc y yu cu dnh cho thit b chn vt. Nh vy sy c gii quytbi cung cp lc y v tng tc gia thit by v dng chy quanh thn v tu.Khi mt vt chuyn ng trong mt cht lng n chu cc lc i nghch vi chiu chuyn ng. Khicon tu chuyn ng trong nc v khng kh n chu c lc cn ca nc v khng kh. Khi lngnc v khng kh c th t chuyn ng bi cc dng i vi nc v khng kh do gi y i.

0

500

1000

1500

2000

2500

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20

Lc cn cm ng (N)


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Thng thng cc ci s c gi trv hng khc nhau. Sc cn c nghin cu ban u trongmi trng nc lng, khng c gi. Dung sai cho php ring c dnh cho chuyn ng ca giv khong cch hiu chnh dnh cho chuyn ng ca nc. Tr khi gi qu to, sc cn ca nc sc nh hng chnh n vic xc nh tc t c.

Dng cht lng

ng hc cht lng cin cho thy hng dng chy qua mt vt th qua hnh di.

Khi cht lng chuyn ng qua vt th, khong khng gian ca dng chy thay i v tc ca dng chy cng thay i do lng cht lng trong dng chy lun khng i. nh lBernoullicho thy c cc thay i tng ng v mt p sut. i vi mt dng chy cho trc, nu p, , v v

h ln lt l p sut, mt ring, tc v chiu cao ct p, khi 2

2

pgh const

Khi nghin cu ng hc cht lng, pht trin mt s tham s khng kch thc rt l hu ch vici c trng cho dng chy v lc. Nhng ci ny da trn c scc c tnh ca cht lng. Ccc tnh vt l thuc v nghin cu sc cn l mt ring , nht , v p sut tnh ca chtlng p. Khi t R l sc cn, V l tc v L l chiu di c trng, vic phn tch thnguyn ati vic biu din sc cn nh sau:

a b c d e f R f L V g p

Lc cn ma st nc RFDo thuyn bay di chuyn lc ct cnh v h cnh l trn mt nc, m nc th c nht nn

cc phn tnc gn thn thuyn s dnh vo v chuyn ng cng thuyn bay to nn mt lp binquanh thn tu tip xc vi nc. ln ca lc cn ma st ph thuc vo b dy lp bin ny.

Thuyn bay nhm chng ti thit k ch yu hot ng trn bin nn kho st iu kin nc

bin c mn 3.5%, nht ng hc l , khi lng ring ca nc bin =1025 kg/m

3.

Lc cn ma st ca thn tu ph thuc vo din tch mt t ca tu v h s cn ring Cf. Lc

cn ma st l phn sc cn ln nht v thng chim 7090% lc cn ca ton btu i vi tutc thp hoc nhhn 40% cc loi tu cao tc.Lc cn ma st c tnh theo cng thc

21. . .2

F f SR C V A


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vi h s cn ring0.5

2

1.3271

2

f

f

R VLC

SV

,

SA l din tch mt t ca v tu vi cng thc tham kho:

= (0,6 + 0,33)(B + 2T) L, vi h s bo 0,35 < < 0,57

Ta xt thuyn bay bay ln c vn tc 20 m/s.

Xem xt chiu di tip xc c trong qu trnh chy ct cnh

Ta c bng lc cn ma st nc theo vn tc

vn tc(m/s)

chiu di tipxc nc (m)

hs cnring ( fC )

din tch mtt (m2)

Lc cn ma stnc (N)

1 7 0.0005 7.56 2

2 7 0.00036 7.56 6

3 7 0.0003 7.56 10

4 7 0.00026 7.56 16

5 7 0.00023 7.56 22

6 7 0.00021 7.56 29

7 7 0.00019 7.56 37

8 7 0.00018 7.56 45

9 7 0.00017 7.56 54

10 6.5 0.00017 7.02 61

11 6.5 0.00016 7.02 70

12 6.5 0.00015 7.02 80

13 6.5 0.00015 7.02 90

14 5 0.00016 5.4 88

15 5 0.00016 5.4 98

16 5 0.00015 5.4 108

17 5 0.00015 5.4 118

18 4 0.00016 4.32 115

19 3 0.00018 3.24 108

20 0 0 0 0

Biu lc cn ma st t theo vn tc


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Lc cn to sng RDVt th chuyn ng trn b mt nc kh phng cng to sthay i trng p sut m trng

t hp li thnh sng do p sut ti b mt l khng i v bng p sut ca kh quyn. T quanst ny khi vt th chuyn dch ti tc n nh, hng sng c vduy tr tng tnh nhau vchuyn ng cng vi vt th. Vi con tu, nng lng to v duy tr sng do hng lc y tu

cung cp. Ni khc i, sng to ra mt lc ko li tu li v tu mun chuyn ng phi c h lcy thng c lc ko li nu tu khng mun chy chm li. Lc ko li c gi l sccn to sng.

tnh lc cn to sng RD ta s s dng l thuyt ca Crewe v Eggington.2 2

. .. . .

c c c cD w w

n n c

P B P S R C C

g g L

xc nh h s lc cn sng Cw ta da vo s Froude v t s Lc/Bc

Vn tc khi tu chy trn nc0.72*9.81*8

2.122 * 4

mgL

V n m/s

200.239

. 9.81*8

VFr

g L

2 2. 64.5

. 8

c c c c

c c c c

L L L L

B B L S

Ta tra th sau:

0

20

40

60

80

100

120

140

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20

Vn tc

Biu lc cn ma st nc theo vn tc

Lc cn mast nc (N)


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H s lc cn to sng Cw = 1.2Thay vo ta tnh c lc cn sng RD l

2 2 2700 *8. . 1.2* 60

. . . 1000*9.81*8

c c c cD w w

n n c

P B P S R C C N

g g L

3.4 Thit ks b Cabin

Cc phng tin giao thng c ch to vi mc ch chnh l chuyn chngi vhng ha, v vy yu cu v thit k ch ngi (hay Cabin) l rt quan trng. Trong thit kthuyn bay cng vy, cng on thit cabin i hi s chnh chu, hp l v n lin quan nthit k tng quan ca ton chic thuyn bay. Tnh ton thit k mt cch hp l cabin smang li nhng hiu qu cn thit nh: tit kim din tch, gim trng lng my bay,


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Yu cu ti l thit k chic thuyn bay l thit k 6 ch ngi (bao gm 1 phi cngv 5 hnh khch), c rt nhiu phng n thit k gh ngi trong cabin v sau nhiu chnla, nhm chng ti i n phng n c xem l ph hp nht:

Vi 6 ngi chng ti sp xp 3 hng gh lin dc thn, din tch ghn 50x50cm,2 hng gh cch nhau 30cm to s thoi mi cho hnh khch, mt gh cch sn 20cm,

lng gh 60cm chiu rng cabin l 1m

Qua cc kho st thc cc phng tin cng chc nng hoc cng kch thc, chiucao trung bnh ca ngi ngi l 80cm, nhm chng ti chn chiu cao cabin l1m, va tit kim din tch va to khong khng va thoi mi cho hnh khch.

Sau y l bn vs b v thit k ca cabin:

Hnh 3.9 Thit k ca cabin.


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3.5 Kt lun thit ks b

Cc thng ss b:

- Khi lng 900kg- Vn tc 80km/h- Thn rng 1m, di 8m- Cnh c bin dng airfoil NACA 4412, din tch cnh 30m2, cnh delta ngc.

Sau cc tnh ton s bta nh hnh c tng th thit k ca thuyn bay, sau y l bn v tngquan:

Hnh 3.10 Tng quan thit k ca thuyn bay.


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Chng 4. Thit k kt cu

Nh chng ta bit, thuyn bay l phng tin s dng hiu ng mt t bay v n hot ng

ct cnh, h cnh ch yu trn mt nc, tc l n l s kt hp gia my bay thng thng v tuthy. V th, kt cu ca thuyn bay l s kt hp gia kt cu cnh ca my bay v thn ca tuthy. Kt cu cnh v thn chnh l hai phn quan trong nht trong tng th kt cu ca thuyn baym chng ta phi ch trng thit k. Phn cnh thng c thit k ln hn so vi my bay thngthng tn dng hiu ng mt t, cn phn thn c thit k ch yu da vo thit k thnthuyn cao tc.

Mt thit k kt cu c bn ca mt chic my bay th thng bao gm 5 mng ln l thn, cnh, bphn n nh, cc b mt iu khin v cng p.i vi thit k thuyn bay th cng tng tnhng do tnh cht hot ng ch yu trn nc nn chng ta khng cn ch n thit kcng p

m nn quan tm n thit k thn thuyn v y l mt khu quan trng quyt nh thnh cng cathit k thuyn bay.

Hnh 4.1 Cc phn chnh trong thit k kt cu my bay.

Khi thit k kt cu thuyn bay th chng ta phi ch n cc ng sut tc dng ln n, ychng ta sxem xt n 5 loi ng sut l ng sut ct, ng sut nn, ng sut ko, ng sut un v

ng sut xon. Vn y l thuyn bay lun phi chu cc ng sut thay i khc nhau trong sutqu trnh hot ng, do phi thit k kt cu v chn vt liu bn thng cc gi tr lc ti agy ra ng sut thay i.

bi thit k ny, nhm chng ti chi vo hai kt cu chnh ca thuyn bay l kt cu thn vcnh. Qua cc thit ktrc y, ngi ta c lng c khi lng kt cu ca cc b phntrn my bay so vi tng khi lng my bay khi cha c hnh khch v hng ha nh sau: kt cuthn v cnh chim 70%, h thng ng c l 20%, h thng in l 10%.

control


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Theo tnh ton s b, ta c trng lng thuyn bay khi khng c hnh khch, hng ha lWo=4500N

t W1 l trng lng kt cu thn

W2 l trng lng kt cu cnh vi nhin liu t trn cnh

W3 gm trng lng kt cu ca thn, ng c

M W1 + W2 = 70% * Wo = 3150N, do chiu di si cnh v chiu di thn gn bng nhau nn taxem xt trng lng ca cnh v thn bng nhau W1 = W2 = 3150/2 = 1575N.

H s an ton bayVic kim sot trng lng thit k th cc k quan trng. Vic tng trng lng yu cu phi c

kt cu cng hn h tr, v iu ny li dn n vic tng trng lng. Vic tng qu trng lng

kt cu c ngha l s gim lng ti c th ch, do nh hng n khnng kinh t ca my bay.V vy, cc nh thit k lun c gng lm gim trng lng my bay mt cch ti a tng thch vimt h san ton. Tuy nhin, m bo m bo cc tiu chun chung v cng v an ton,m bo iu kin bay th my bay phi p ng mt vi h san ton. l ti gii hn(limit factor), tc ti trng ti a m my bay c th hot ng bnh thng, ti th nghim (proofload) l kt qu ca ti gii hn v h s th nghim (11.25), v ti trng ti hn (ultimate load) lht qu ca ti gii hn v h s ti hn (1.5). Kt cu ca my bay phi chu c ti th nghimm khng c s bin dng bt li no xy ra cho n khi t c ti ti hn.

Phn tch kt cuKt cu chung ca mt my bay c thit k h trhai loi ti ring bit: u tin, l ti mtt (ground loads), bao gm tt c ti trng m my bay gp phi trong sut qu trnh my bay dichuyn trn mt t nh ti trng lc chy v h cnh, ti ko v nng, thhai, l ti trnkhng (air loads), bao gm ti tc dng ln kt cu trong sut qu trnh bay.

Ngoi ra, my bay c thit k cho cc ti c vai tr c th gp phi c th cho cc phm vi hotng ca chng. V dnh, my bay trn tu sn bay th c b phng khi ct cnh v hm khi hcnh, hu ht cc my bay dn s ln v cc my bay qun su c cabin iu p bay caoln, my bay li nc phi c khnng h cnh trn mt nc, v my bay thit k bay vi vn

tc cao cao thp, tt cu i hi c mt kt cu cng trn mc bnh thng chu c tcng ca chuyn bay iu kin khng kh v cng hn lon. Trong thit k ca thuyn bay thchng ta ch trng n vn hiu ng mt t.

Hai loi ti c thc chia thnh cc lc b mt tc ng trn b mt kt cu, nh p sut kh ngv thy ng. Vc bn tt c cc ti trn khng l kt qu ca s phn b p sut trn b mt cav, n to ra ti trc tip, un, ct v xon trn tt c cc phn ca kt cu.


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Mt my bay thng thng gm c cc thnh phn chnh l thn, cnh v ui. Thn my bay ccha phi hnh on, ti trng, sau ny c thl hnh khch, hng ha, v kh, nhin liu d tr thythuc vo tng loi my bay v chc nng ca n. Cnh th cung cp lc nng v ui l b phnchnh iu khin hng. Ngoi ra, aileron, alevator, rudder cho php phi cng iu khin my bayv duy tr sn nh ca n trong khi bay, trong khi flap cnh cung cp sgia tng lc nng cnthit khi ct cnh v h cnh.

Cc lc trn b mt kh ng (cnh, ui ng hay ui ngang) l kt qu t s phn b p sut khcnhau do gc ti, camber, hoc chai. Xem xt hnh di ta nhn thy v tr tm p sut CP thayi khi s phn b p sut thay i vi tc v gc t cnh.

Tuy nhin, c mt im theo mt ct airfoil m ti moment gy ra bi lc nng v lc cn l hngs. Do chng ta thay lc nng v lc cn ti tm p CP bi lc nng v lc cn ti tm kh ngAC cng thm moment khng i Mo.

trn l s phn b p sut theo chord cnh, sau y l s phn b p sut theo si cnh.


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Chng ta thy rng cnh, ui, v thn u chu cc ti vung gc, un, ct, xon v phi c thitk chu c s kt hp ca cc ti ny. Ngoi cc ti trng c bn trong qu trnh bay, thn cth chu p sut cao v do h trcho cc ng sut vnh ai, cnh c th mang thm nhin liu tothm lc kh ng v lc khi gp phn lm tng s un, ct v xon, trong khi lc y v trnglng ca ng c c thnh hng n thn v cnh da trn v tr lin quan.

Ti mt thong gp phi khi chun b ct cnh v lc hcnh tc ng ln thuyn bay ch yu l tiva p ca thn thuyn. Chnh iu ny i hi phi thit k kt cu thn thuyn mt cch klng n c th chu c va p khi h cnh, hoc khi di chuyn trn mt nc.

Cc ti trng khc c th bao gm lc y ng c trn cnh hoc thn, trong trng hp ng c bhng s gy ra moment un thn, ti gy sc tp trung trong qu trnh di chuyn v p sut thyng tc ng vo thn tu.

4.1 Kt cu thn thuyn bay

Cng ging nh my bay v thuyn, thn thuyn bay l ni m tt c thnh phn v ti t vo.Vic trng hot ng c trn mt nc v trong khng kh nn cc thit k thn ca thuyn bay phim bo c c v mt thy ng v kh ng.

gim thiu lc cn thy ng hc, b mt di ca thn my bay m tip tc vi mt nc cthit k da vo cch thit k thn thuyn c ch to v ph hp vi thuyn bay. Mt khc, khi

trong khng kh, thuyn bay s hot ng nh mt my bay thng thng, nn gim thiu lc cnkh ng hc, thn my bay c thit k vt l mt cch hp l tc kh ng thp. Tng tnh mt airfoil vn tc thp, mi ca thn my bay c thit k cng bo trn cng tt v ui thmng nht c thdng kh lu thng qua c thng sut v khng bt qung nhiu.

Bi thuyn bay c cu hnh tng t mt my bay cnh cnh nn kt cu thn c thit k kiuna lin bao gm v, sng dc, khung vng.


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4.1.1 Cc ti trn thn thuyn bay

Chng ta xem xt cc ti tc dng ln thn bao gm: [Tham kho 8]

Ti i xng Ti khng i xng Ti tc ng khi h cnh trn mt nc (h cnh bng mi, bng thn, hay bng ui)

Trong trng hp ti i xng th ta c h s ti bng 2 vn tc bay ti a, trng hp ti khngi xng l do moment un v xon ngang ca ui ng, v trng hp ti gn nh tnh khi hcnh bng mi, thn (thng thng) v bng ui.

a) Ti i xngTheo cc kt qu nghin cu trc y, tng trng ti ti a ca my bay cnh cnh c thcchia thnh lc nng cnh chnh, lc nng ui ngang, v ti qun tnh ca c my bay vn tc tia c mi quan h sau.

WB TnW L L

Vi, n = h s ti trng, W = trng lng my bay, LWB = lc nng ca cnh v thn, LT = lc nngui ngang. y ta xem xt rng thn ch to ra khong 3% so vi LWB, v do lc nng thn cthc b qua khi thit k.

b) Ti khng i xngTi khng i xng l moment un v xon ngang ca ui ng, do tng moment xon T c thc th hin bi phng trnh sau:

0.1F F T F F T L h L b L h

Vi, LF lc nng ui ngang, hF khong cnh ng ttm kh ng ca ui ng n trng tm cathn, 0.1LT s sai lch lc nng gia bn tri v bn phi ca ui ngang (tuy nhin s sai lch nyrt nh, c th bqua c), b khong cch ngang ttm kh ng ca ui ngang n trong tmca thn.

c) Ti tc dng khi h cnhc nh ngha l ti tc dng gn nhtnh ti mi, thn hay ui hng, tng ng. Theo ccnghin cu trc y, ngi ta tm thy rng ti trng ln nht l khi h cnh bng thn gia. Tuynhin, khi phn tch ng sut ta phi xem xt tt c cc ti tc ng ti 3 v tr. Ti tc dng gn nhtnh khi hcnh c th hin bi phng trnh sau:

3 2/3

max9 10A M


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ee FP

A

. .e e

F n M g

Vi, pe p sut ti khu vc tc dng, A din tch tc dng, Fe ti tc dng, ne h s ti tc dng = 1.5.

4.1.2 Thit k v v thanh dm.

Da vo mt s ginh rng v my bay ch yu chu ti ct v vnh, cn thanh dm ch yu chumoment un. Mi quan h gia ng sut ct v un cho php vi ti ca chng c xc nh nhsau:

max

max

4

3 2

4

alowable

alowable

s i

V

Rt

M

A y

Do , hnh dng mt ct ngang c thc xc nh bng cc ti trn. Tuy nhin do hu ht vurt yu khi b ti vnh do dy mng, v c thc thit kban u da vo vnh.

22

2

22

2

12(1 )

12(1 )

cr c

cr s

E tK

b

E tK

b

Cc h s vnh Kc , Ks c thc tm t biu ti vnh ca v cong2

2 1/ 2(1 )b

Zrt

, r/t l t s

gia bn knh v b dy, a/b t s gia chiu di v rng. Kt qul, iu kin an ton ca cc thitk c thc c bng cch s dng t lng sut ct v ng sut php:

2

,

1, _

t qbc s

cr cr

c s

R R

R R safety condition

Vi 3/ / (2 ), ( ),b b A y t q l r M y I T r t q q ql l dng st vng trn, qr dng ct dc.


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4.1.3 Thit k khung vng

Khung vng gn cnh chnh c thit k bng cch di chuyn moment un t cnh chnh v tict ng theo khu vc. Moment un cc b v ti trc ca khung vng c thc tnh ton v sau c th hnh dng mt ct ngang ca khung vng. Cc khung vng khc c thc thit ktngtnh khung vm cnh chnh.

2

1 11

( ) ( ). . ( ) 0

q

o o

My y y yM s P s y y s

I I I

Mq moment un do dng ct q to ra t ti ng cc b.

4.1.4 Tnh ton s b kt cu thn

Thng skch thc thn gm, di 8m, rng 1m.

M hnh ha mt ct ngang kt cu thn tnh ton ng sut.

Vi bending moment Mx = 9000 Nm. Phn b v din tch cc boom nh hnh trn.


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42

V mt ct i xng theo trc y (Ix,y = 0), v My= 0, ta c phng trnh ng sut ca bendingmoment :

xx

xx

My

I

Xc nh ng trung bnh:

1.8 6.4 2 1.48 6 2 1.24 6 2 0.99 6 2 0.75 6.2 2 0.4 6.4 2 0.22 6.4 2 0.08 7.5

6.4 6 6 6 6.2 2 7.5 2

x x x x x x x x x x x x x x xy

x x x x

0.73y m

Bng tnh ton ng sut

Boom y (m) B (10^-4 x m2) Ixx = By^2 (m4) (Mpa)1 1.07 6.4 7.3 446

2 0.75 6 3.4 312

3 0.51 6 1.6 212

4 0.26 6 0.4 108

5 0.02 6.2 0.0 8

6 -0.33 6.4 0.7 -137

7 -0.51 6.4 1.7 -212

8 -0.65 7.5 3.2 -271

9 -0.73 6.4 3.4 -304

Ixx = 21.6


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4.2 Phn tch ti tc dng ln cnh

4.2.1 Xem xt lc nng kh ng

Phn phi lc nng kh ng trn cnh

Hnh 4.2 Phn b lc nng ellip trn cnh.

Lc nng trn cnh c c tnh bng phn b ellip 2 2( )l

q x ka l x

Chng ta tnh tng lc nng bng cch tch phn ( )lq x theo chiu di cnh l :

22 2

0 4

ll ka

L ka l x dx

(1)

Vi h s ti n (load factor) l t s lc nng vi tng khi lng thuyn bay0

Ln

W (2)

Lu y chng ta ch xt lc nng phn b trn 2 cnh.

T (1) v (2) ta c:2

0

2 4

nW l ka 0

2

2nWka

l

Vi kt qutrn ta c c phn b lc nng ellip2 2

0

22( )l nW l xq x

l

Vi thit ks b cnh ca thuyn bay ta c Wo = 900kg, chiu di 1 bn cnh l l = 3m, h s lc

nng L = 9000N, ta xt ti 11 v tr trn 1 bn cnh (xt t ngoi vo thn)


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44

x 2.9 2.62 2.34 2.06 1.78 1.5 1.22 0.94 0.66 0.38 0.1

q(x) 489 930 1195 1388 1537 1654 1745 1814 1863 1895 1909

T bng trn ta c biu phn b lc nng kh ng trn cnh

Hnh 4.3 Biu phn b lc nng trn cnh.

4.2.2 Xem xt ti ttrng lng cnh

Bn cnh lc nng, cnh cng chu ti trng xung do trng lng cnh gy ra, ngoi ra c th cnc trng lng ca nhin liu lu tr. y chng ti ch phn tch ti trn m hnh cnh.

Kt cu cnhTi do trng lng kt cu cnh gy ra c m thnh sau:

Hnh 4.4 Phn b ti do trng lng kt cu cnh.

0

500

1000

1500

2000

2500

1 2 3 4 5 6 7 8 9 10 11

Tilctcdng

V tr trn cnh

x

q(x)


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45

Chng ta ginh rng ti t l thun vi chiu di chord cnh, ln nht gc cnh cr v thun nhntuyn tnh n ngn cnh ct. Phn b ti c th hin qua phng trnh sau:

( )/ 2

t rw r

c cq x kw x c

l

Tch phn ( )wq x theo chiu di cnh ta sc tng ti do trng lng kt cu cnh gy ra:

* ( )

2

r tl kw c c

StructTotalLoad

Tng tnh khi tnh lc nng kh ng, ta c* ( )

2 2

w r tnW l kw c c ( )

w

r t

nWkw

l c c

Cui cng ta c c phn b ti:

( )( )

( )

( )

r tw r

w

r t

x c cnW c

lq x

l c c

Trng lng kt cu cnh Ww = W2 = 1575N, cr = 7m, ct = 3m

ta xt ti 11 v tr trn 1 bn cnh (xt t ngoi vo thn)

x 2.9 2.62 2.34 2.06 1.78 1.5 1.22 0.94 0.66 0.38 0.1

q(x) -165 -184 -204 -223 -243 -263 -282 -302 -321 -341 -361

Ta c c biu phn b ti t trng lng cnh

Hnh 4.5 Biu phn b ti trng lng cnh.

-400

-350

-300

-250

-200

-150

-100

-50

0

50

1 2 3 4 5 6 7 8 9 10 11

Titrnglngcnh

V tr trn cnh

q(x)

x


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46

4.2.3 Xem xt ti nhin liu t trn cnh

Vic t nhin liu trn cnh l mt thit k ph bin bi v trng lng ca nhin liu chng li lcnng, lm gim ti rng trn cnh. Ti nhin liu c m tnh sau:

Hnh 4.6 Phn b ti nhin liu t trn cnh.

ln ca ti nhin liu c tnh ton nh ti kt cu cnh, ta c:

( )

rf tf

f rf

f

f

f rf tf

x c cnW c

L

q x L c c

Trong thit k thuyn bay th ti do nhin liu c gp chung vo phn tnh do ti trng lngcnh.

4.2.4 Xt trng hp ti tng cng

Ta tnh ton ti tng cng bng cch tnh cng lc ti do lc nng, trng lng v nhin liu cng

t trn cnh ta c:

2 2

0

2

( )( )

2( )

( )

r tw r

l

r t

x c cnW c

nW l x lq xl l c c

Ta c bng s liu


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47

x 2.9 2.62 2.34 2.06 1.78 1.5 1.22 0.94 0.66 0.38 0.1

q(x) 324 746 991 1165 1294 1391 1463 1512 1542 1554 1548

Hnh 4.7 Biu tng ti lc tc dng ln cnh.

Tnh ton phn b lc trn cnh

xc nh phn b p sut theo chiu di si cnh, ta s dng phng php xp x ca Schrek. Tphn b si cnh, p sut phn phi trn b mt c thc c bng cch chia n theo chiu dichord cnh.

Hnh 4.3: Phn b lc nng theo sai cnh v chord cnh.

0

200

400

600

800

1000

1200

1400

1600

1800

0 0.5 1 1.5 2 2.5 3 3.5

q(x)

q(x)


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48

Phng php ti xp x ca Schrek l phng php thng c s dng xc nh phn phi tngth lc nng trn cnh, c bit cho cnh c gc sweep nh v h s aspect ratio trung bnh n cao.Ti phn bc th hin qua phn b ellip theo chiu di si cnh.

Ta c phng trnh phn b ti hnh ellip:2

1

4 21

y

L yw

b b

Vi, L l tng lc nng trn cnh = 9000N.

Chiu di si cnh b = 6m, y l v tr theo si cnh.

Ta c bng phn b ti 1 bn cnh (vi khong chia l 7)

y (m) 0.428 0.856 1.284 1.712 2.142 2.562 2.987

w (kN/m) 1.89 1.83 1.726 1.568 1.337 0.994 0.178

Phng trnh phn b hnh thang: 22 2

1 ( 1)(1 )

y

L yw

b b

Vi l h s taper = cr / ct = 7/3 = 2.33

Bng phn b 1 bn cnh (7 khong chia)

y (m) 0.428 0.856 1.284 1.712 2.142 2.562 2.987

w (kN/m) 1.072 1.243 1.415 1.584 1.756 1.942 2.113

Cng thc ti xp x ca Schrenk:y1 y2

2

w ww

y (m) 0.428 0.856 1.284 1.712 2.142 2.562 2.987

w (kN/m) 1.481 1.537 1.571 1.576 1.547 1.468 1.146


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49

Hnh 4.4: Biu phn b ti 1 bn cnh

Tip theo, chia tai theo chiu di chord cnh ti mi vtr y tng ng c c phn b p sutdc theo chord cnh (c = 3m). Ta tnh ra c chiu di chord ti mi v try tng ng theo cngthc sau:

2 2

( ) 1 1(1 )

S yc y

b b

y (m) 0.428 0.856 1.284 1.712 2.142 2.562 2.987

w (kN/m) 1.481 1.537 1.571 1.576 1.547 1.468 1.146

c (m) 6.43 5.86 5.28 4.71 4.14 3.57 3.15

P (kN/m2) 0.23 0.262 0.298 0.335 0.374 0.411 0.364

Vi cc phng trnh Q(x), M(x)

(){

(())

(())

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

1.8

0.428 0.856 1.284 1.712 2.142 2.562 2.987

w(k

N/m)

V tr y

w (kN/m)


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50

(){

(())

()

(())

()

Ta tnh ton c im chu bending moment ln nht l ti wing root khong 9000 Nm.

Ta m hnh ha kt cu cnh tnh ton

Ta m hnh ha thnh cc beam k hiu B1 = B8, B2 = B7, B3 = B6, B4 = B5 tnh din tch.

Vi cng thc tnh tng beam 26j

i

i

LtB

trong trng hp ny

j j

i i

y

y

Din tch cc beam l

821 101 1

0.04*1.44 0.05*0.32 2

6 6B B

20.04 *1.44 0.4 0.05 * 0.3

2 2 1 0.04736 0.15 6

m

3 9 12 9

2 2 2

0.03*2 0.04*1 0.04*1.442 2 2

6 6 6B B

20.03* 2 0.4 0.04*1 0.4 0.04 *1.44 0.152 2 2 0.05956 0.4 6 0.4 6 0.4

m

12

8

3

7

4

65

5

910

x

y


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51

84 23 8

3 3 3

0.03* 2.01 0.04*1 0.04* 22 2 2

6 6 6B B

20.03* 2.01 0.3 0.04 * 0.8 0.4 0.04 * 2 0.42 2 2 0.0736 0.4 6 0.4 6 0.4

m

3 5 74 74 4 3

0.03* 2.01 0.02*1.62 0.03*0.62 2 2

6 6 6B B

20.03* 2.01 0.4 0.02 *1.62 0.05 0.03* 0.6 0.252 2 2 0.051336 0.25 6 0.25 6 0.25

m

645 65 5

0.02*1.62 0.02*0.12 2

6 6B B

20.02 *1.62 0.25 0.02 * 0.1 0.052 2 0.0381

6 0.05 6 0.05

m

Vy ta c c din tch cc beam m hnh ha.

Bng tnh ton kt cu thc:


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52

Ta c c ng sut ti cc boom, so snh vi ng sut vt liu kt cu ta c th bit cphn b kt cu boom nh vy l hp l hay cha v c thiu chnh li.

4.3 Tnh ton gii hn mi

Tui th mi ph hy ca mt thnh phn kt cu thng c nh ngha l thi gian hnh thnhvt nt m c xu hng lm gim cng ti hn ca thnh phn .

Tui th mi bao hm tui thtrung bnh c d kin theo khnng hot ng ca my bay v titc dng tmi trng. thit k tui th mi, ng dng ca cc h s phn tn tui th mi chocc bin th c th t vic s dng trung bnh, mi trng ti, v cng mi cho php. Vic nydn n mt chu k tui th an ton rt thp khi m xc sut vt nt kt cu xy ra. Vi tui thkhng an ton, thit k c thquan st c, tui th kt cu tht s cao hn nhiu.

Tui th mi tng cng ca my bay l thi gian m ti vic sa cha cu trc khng cn kh thiv mt kinh t.

H s an ton t 24 c s dng kim tra cho cc bin th thng k trong khi kim tra thnhphn mi m cha bit r ti.


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4.4 Vt liu

Vic chn vt liu khng ch da vo t l bn vi trng lng m cn ph thuc vo cc thngs khc:

cng ph hy lan truyn vt nt nhy ng sut chng n mn

Yu t quan trng trong chn vt liu l phi va bn va nh. Ngy nay vi s pht trin ca cngngh vt liu, chng ta c rt nhiu loi vt liu siu nhnhng li p ng c bn rt ln.

Qua cc kho st, chng ti thy c vt liu ch yu s dng cho my bay l hp kim gm nhm,magie, titan, thp,v chng c th b sung nhng tnh cht m kim loi gc khng c c. Ccloi hp kim ny c s dng rt nhiu ch to my bay nhng gn y c mt loi vt liu mil composite c nhng tnh nng vt tri hn so vi cc hp kim trn. Chnh v l do chng ti

s chn composite lm vt liu chnh trong thit k thuyn bay.

Tnh u vit ca vt liu Composite l khnng ch to t vt liu ny thnh cc kt cu sn phmtheo nhng yu cu k thut khc nhau m ta mong mun, cc thnh phn ct ca Composite c cng, bn c hc cao, vt liu nn lun m bo cho cc thnh phn lin kt hi ha to nn cckt cu c khnng chu nhit v chu sn mn ca vt liu trong iu kin khc nghit ca mitrng. Mt trong cc ng dng c hiu qu nht l Composite polyme, y l vt liu c nhiutnh u vit v c khnng p dng rng ri, tnh cht ni bt l nh, bn cao, chu mi trng,d lp t, c bn ring, cc c trng n hi cao, bn vng vi mi trng n mn ha hc, dn nhit, dn in thp. Khi ch to mt nhit v p sut nht nh d trin khai c cc th

php cng ngh, thun li cho qu trnh sn xut. [Tham kho 8]


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Chng 5. Phn tchn nh v iu khin5.1 Khi nim n nh

n nh l khuynh hng ca my bay trv trng thi trc nu my bay chu tc ng bi mt

nhiu, nh gi hay vng khng kh khng n nh. Nguyn nhn ca s nhiu lon ny l do tcng ca phi cng hoc do nh hng ca iu kin kh quyn bn ngoi (gi, dng kh bt nnh,) trong sut qu trnh bay.

Sn nh (Stability) c xc lp ch khi my bay trng thi "trim", tc l trng thi m khng c nhng lc v nhng moment mt cn bng tc ng ln my bay lm cho n lch khich bay bng. Mt my bay c thc n nh theo mt siu kin ca chuyn bay v khngn nh theo cc iu kin khc. Kim sot c ngha l khnng ca phi cng iu khin my baytheo bt k v t mong mun.

Nh ni, mt my bay, khi b nhiu, n c xu hng trli vtr ban u th c cho l n nh,cn ngc li, n khng n nh. Nhng n c thc xu hng khng trli m lun trong v trmi. iu ny c gi l n nh phim nh, i khi n l mt tnh nng rt mong i.

n nh c chia lm 2 loi phn tch l n nh tnh v n nh ng.

Hnh 5.1 Cc nh ngha vn nh.


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Hnh 5.2 n nh ng.

5.2 Kho st n nh kh ng

V mt kh ng th thit k thuyn bay cng cn m bo cc yu cu vn nh tnh v n nhng nh mt my bay thng thng.

5.2.1 n nh tnh

Trong phn n nh tnh ta s ln lt xt cc trng thi n nh sau ca my bay v nhn xtca tng trng hp:

- n nh theo phng dc: xt pitching moment M- n nh theo hng: xt yawing moment N- n nh ln: xt rolling moment L

Trong phn ny ta s tnh ton cc h s sau:0

, , , , ,m m N cg NP trimC C C x x

a) n nh tnh dcnh gi nh hng sn nh ca my bay theo phng dc th ta phi da vo h s mC

v0m

C

iu kin n nh tnh dc l00

mo

m

CC

Ta xt snh hng ca thnh phn cnh (wing), ui ngang + ui ng (tail) v phn thn

(fuselage) v tr 30%cgx c theo cng thc:,w ,w , ,cg ft cg cg f cg t m m m m

C C C C


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57

nh hng ca cnh

,w 0,w 0,cg wm m L wC C C vi:

0,w ,w 0,w

,w ,w

(1)

(2)

ac

cg acm m L

cg ac

m L

x xC C C

c c

x xC C

c c

Tham kho mt s chic thuyn bay thit k th ta c mt s thng s tham kho sau: (do khngthtnh ton kim chng nn ta tm ly kt quny kho st) (vi bin dng cnh 4412)

/ 0.42 ; / 0.45; 0.088cg ac macx c x c C

T gi tr xac/c, [tham kho 5] ta c moment ti tm kh ng cao h = 0.1c v gc tibng 3o l 0.0635

acwm

C

Ta c hm h s lc nng theo gc ti v cao :

6 10 6 101.268 0.406645 0.05942 0.0024 5 4 5ow

L

h hC

Khi 0 ; 0.1o h c ta c:0

0.767wL

C

ta thay vo phng trnh (1) v (2), ta c,w w

-0.2644 0.767 (1/ )cgm

C rad

- Xc nh:1.19

/44.44 cos

A H c

dK K K

d

Trong :

A = 3 , 1.7 1.71 1 1 1

0.19951 3 1 3AK A A

/40

c , 1 do cnh hnh ch nht.

10 3 10 3 11

7 7K

Ta c: 4 ; 1.2H Hl m h m

3 3

1.21 1

6 0.72682 2 4

6

H

H

H

h

bK

l

b

Vy: 1.19 1.19

/44.44 cos 4.44 0.1995 1 0.7268 1 0.446

A H c

dK K K

d


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58

- Xc nh VH:cS

SzlV

twcgt

Ht

)sin(

Trong :

ltl khong cch t tm kh ng ca ui n trng tm thuyn bay khong lt = 4.5 m.

tcgz = 1.2 m (khong cch cao t trng tm thuyn bay n tm kh ng ui).

o

w 3 , gc ti khi bay bng.

wod

d

, vi

0.7670.081 4.6 .

3

owL o

o

w

Crad

AR

4.6 0.658 3 6.6 .o

sin( ) 4.5 1.2 sin 3 6.6 4.050.2646

30 3

tt cg w t

H

l z SV

Sc

Ta chn bin dng cnh cho ui ngang l NACA 0009 c dc ng lc nng ca airfoill 1 10.1deg 5.732

tL

C rad

H s moment ti tm kh ng ca ui vi NACA 0009 ltac

mC = - 0.055.

T hm h s lc nng theo gc ti v cao :

WLoC = 1.268 +0.406645

o hm h s lc nng theo gc ti ta cw

LC = 0.102 deg-1

= 5.84 rad-1

.

Sau khi xc nh c cc thng s cn thit ta c th tnh c cc h som

C vm

C

ca thuyn bay kim tra n nh dc theo gc pitch.

Trong :

wacm

C = 0.0635;w

LC 0 = 0.767; xcg/c = 0.42; xac/c = 0.45; 1 .

VH = 0.2646 ;t

LC = 5.732; 4.6o

o ; it = 1

o;

tacmC = - 0.055.

Thay s vo ta c:

5

10

4

6002.0

5

1005942.0

4

6 HH

tactwwactw

mtoLHaccg

LmmmmCiCV

c

x

c

xCCCCC

0000


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59

omC = 0.0635 + 0.767x(0.420.45) + 1x0.1163x5.732x(4.61 )/57.30.055

omC = 0.027.

Viw

LC = 5.84 rad-1

;

d

d= 0.658.

mC = 5.84(0.420.45)1x0.1163x5.732x(10.446) = - 0.5445.

Vy phng trnh c vit nh sau:

0.027 0.5445cg

mC

00

0

m

m

C

dC

d

thuyn bay ang thit k tha iu kin n nh tnh dc.

5.3 Kho st n nh thy ng

Do thuyn bay ct cnh v h cnh trn mt nc nn phn thit kn nh thy tnh th rt cn thitm bo hot ng ca n lc ct h cnh. Phn tnh ton kho st n nh thy ng ca thuynbay th lin quan n cc tnh ton n nh ca tu cao tc.

Lc y Archimede W = F = gV

Hnh 5.3 Lc y Achimede.

d

dCV

c

x

c

xCCCC

twtwLH

accg

Lmmm 1

mmm

CCCcg

0


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60

Vi, G : trng tm thn thuyn, B l tm nh khuynh.

Tm nh khuynh l trng tm khi lu cht m vt chim ch.

n nh l khnng cn bng ca thn thuyn khi chu cc lc c xu hng lm nghing thuyn.Cc lc ny thng tnh, nh p lc gi len thuyn, nhng khi gp bo c thmang n cc lcng (gi lc hoc sng ph v). nh gi sn nh tng th ca mt thuyn bay m i hi phixem xt cn nh tnh v ng.

Hnh 5.4 C chn nh.

Bn yu tc lin quan n n nh thuyn l:

Trng tm (n nh dn) G Tm nh khuynh (n nh dng) B Chuyn v (nh hng n nh tnh v ng) Moment qun tnh (n nh ng)

Nu G thp hn B th cn bng n nh, nu trong mt iu kin no , vt dch ra khi v tr cnbng th di tc dng ca ngu lc to ra bi W v F th vt s trli vtr ban u.

Nu G cao hn B th cn bng khng n nh, nu vt dch khi v tr cn bng th di tc dng ca

ngu lc th vt s cng ra xa vtr ban u.

Nu G trng B th cn bng phim nh, tc vt cn bng n nh bt k v tr no.

Ni chung, chng ta cn thit k thn thuyn sao cho v tr trng tm c h thp nht c th mkhng nh hng n tm ni, n sm bo n nh v mt tm nh khuynh cho thn thuyn.

F F


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61

Chng 6Kt lunMu m hnh thuyn bay m nhm thc hin


62/62


Ti liu tham kho:

1. http://www.se-technology.com/wig/index.php?open=concept2. http://www.ikarus342000.com/INTRO2.htm3. http://hoverwing.webs.com/groundeffectbasics.htm4. http://aerospace.eng.usm.my/rcp/index.php/analysis/finite-element-analysis-fea/wideeye5. Lun vn tt nghip Hunh Thy Ha Mi lp Vit Php kha 996. Thit k thuyn bay Trn Vn c HK077. Lun vn tt nghip u Vn Hun kha 20008. http://www.iccm-central.org/Proceedings/ICCM16proceedings/contents/pdf/WedJ/WeJA1-

02ge_kimj226906p.pdf

9. http://www.hungvietcomposite.com/Vat-lieu-Composite.49.html10.Ngoi ra cn cc ti liu khc trn mng khng r ngun gc.
http://www.se-technology.com/wig/index.php?open=concepthttp://www.ikarus342000.com/INTRO2.htmhttp://hoverwing.webs.com/groundeffectbasics.htmhttp://aerospace.eng.usm.my/rcp/index.php/analysis/finite-element-analysis-fea/wideeyehttp://www.iccm-central.org/Proceedings/ICCM16proceedings/contents/pdf/WedJ/WeJA1-02ge_kimj226906p.pdfhttp://www.iccm-central.org/Proceedings/ICCM16proceedings/contents/pdf/WedJ/WeJA1-02ge_kimj226906p.pdfhttp://www.iccm-central.org/Proceedings/ICCM16proceedings/contents/pdf/WedJ/WeJA1-02ge_kimj226906p.pdfhttp://www.iccm-central.org/Proceedings/ICCM16proceedings/contents/pdf/WedJ/WeJA1-02ge_kimj226906p.pdfhttp://www.hungvietcomposite.com/Vat-lieu-Composite.49.htmlhttp://www.hungvietcomposite.com/Vat-lieu-Composite.49.htmlhttp://www.iccm-central.org/Proceedings/ICCM16proceedings/contents/pdf/WedJ/WeJA1-02ge_kimj226906p.pdfhttp://www.iccm-central.org/Proceedings/ICCM16proceedings/contents/pdf/WedJ/WeJA1-02ge_kimj226906p.pdfhttp://aerospace.eng.usm.my/rcp/index.php/analysis/finite-element-analysis-fea/wideeyehttp://hoverwing.webs.com/groundeffectbasics.htmhttp://www.ikarus342000.com/INTRO2.htmhttp://www.se-technology.com/wig/index.php?open=concept

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